1-Click Duplicate Delete for Outlook

1-Click Duplicate Delete for Outlook screenshots

This program is a nice Outlook utility created by ITSTH
Outlook Button
1-Click Duplicate Delete for Outlook 3.1 : Outlook Button

Alternative downloads

Duplicates Remover for Outlook
A plugin for the search and processing of duplicates in Outlook folders.
Deduper for Outlook
Find and delete Outlook duplicates with one mouse click.
SysTools Duplicate Outlook Contacts Remover
It is an application which can help you delete Outlook duplicate contacts.